how to convert xml as another xml using php

[Artificial.Intelligence]

I want to convert one xml to another xml.for example if xml tag as string,\[code\]<book><title>test</test><isbn>1234567890</isbn><author>test</author><publisher>xyz publishing</publisher></book>\[/code\]i want to convert above xml as,\[code\]<b00><t001>test</t001><a001>1234567890</a001><a002>test</a002><p001>xyz publishing </p001></b00>\[/code\]how to convert xml using php